JP5304320B2 - Recording paper transport path structure and printer - Google Patents

Description

  The present invention relates to a printer having a suction platen that sucks and transports recording paper to a platen surface that defines a printing position, and in particular, is fed to the platen surface via a nip portion of a paper feed roller and a paper press roller. The present invention relates to a recording paper conveyance path structure for guiding recording paper.

  In a printer, for example, an ink jet printer, it is important from the viewpoint of ensuring printing quality that a recording paper is brought into close contact with a platen surface defining a printing position to ensure a platen gap with high accuracy. In order to transport the recording paper while bringing the recording paper into close contact with the platen surface, a suction platen that transports the recording paper while sucking air onto the platen surface is used. In particular, since long roll paper, fanfold paper, and the like have curls and creases, it is desirable to forcibly hold the recording paper flat using a suction platen. A printer provided with a suction platen is disclosed in Patent Documents 1 and 2.

JP 2001-221946 A Japanese Patent No. 3864791

  Here, when the part of the recording paper sent out from the nip part of the paper feed roller and paper pressing roller to the platen surface of the suction platen is sent out in the direction of lifting from the platen surface, a gap is created between the recording paper and the platen surface, There may be a case where a negative pressure state due to air suction cannot be formed between them, and the recording paper cannot be sucked onto the platen surface. Therefore, the recording paper sent out from the nip portion between the rollers to the platen surface is not parallel to the platen surface, but the recording paper sent out from the nip portion so as to incline toward the platen surface. It is desirable to feed the paper portion so as to press it against the platen surface.

  However, when such a recording paper conveyance structure is adopted, there are the following problems. That is, as shown in FIG. 7, in order to feed the recording paper 100 in the direction of pressing toward the platen surface 102 of the suction platen 101, a step A is formed between the nip portion 105 between the rollers 103 and 104 and the platen surface 102. It is necessary to attach. When the nip portion 105 and the platen surface 102 are at the same height, the recording paper 100 fed from the nip portion 105 is guided from the end 102a of the platen surface 102 while being supported by the platen surface 102, but the step A If there is, the portion of the recording paper 100 fed out from the nip portion 102 comes into contact with the platen surface at a position downstream of the end of the platen surface in the transport direction, as indicated by a one-dot chain line B.

  When there is a step, the distance until the recording paper 100 fed from the nip 105 is supported by the platen surface 102 becomes longer, and the portion of the recording paper 100 that is transferred from the nip 105 to the platen surface 102. Is conveyed in a bent state as indicated by a two-dot chain line C by the suction force of the suction platen 101.

  For this reason, when the portion of the recording paper 100 with the bent creases and creases is fed out from the nip portion 105, the recording paper 100 may be greatly bent in the direction of dropping into the gap 110 between the nip portion 105 and the end 102a of the platen surface. . When the recording paper 100 is greatly deflected, the feeding amount of the portion of the recording paper 100 conveyed along the platen surface 102 is reduced by the amount of deflection with respect to the feeding amount of the portion of the recording paper 100 fed from the nip portion 105. End up. As a result, the paper feed amount is insufficient and the paper feed accuracy is lowered, so that the dot pitch by the ink jet head may be disturbed and the print quality may be deteriorated.

  In particular, in the case of recording paper such as fanfold paper, the strength of the waist is greatly different in each part in the length direction. For example, since the fold portion of the fanfold paper is particularly weak, when the fold portion is handed over from the nip portion to the platen surface, the crease portion is bent and falls into the gap 110 between them as shown by the broken line D. There is a possibility that the sheet will be greatly bent and pinched between the suction platen 102 and the roller 103, resulting in a paper jam.

  SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to prevent a decrease in paper feeding accuracy by suppressing the bending of the recording paper fed from the nip portion of a pair of rollers to the platen surface of the suction platen. It is to propose a conveyance path structure and a printer having the recording paper conveyance path structure.

In order to solve the above problems, the present invention provides a recording paper conveyance path structure for sending a recording paper to a platen surface of a suction platen facing a print head through a nip portion of a pair of rollers, The nip portion is at a position offset to the print head side with respect to the platen surface, and a tangential plane passing through the nip portion approaches the platen surface as it goes from the nip portion to the platen surface. The pair of rollers are arranged so as to be inclined to each other , and on the side of the nip portion of the platen surface, the side of the print head toward the side of the nip portion of the platen surface. A guide surface that has an inclined surface portion that guides the recording paper fed from the nip portion is formed, and the guide surface has a height that does not protrude from the tangential plane. , And the inclination of the inclined surface of the guide surface is characterized in that the is an inclined angle along the tangent plane.

  The recording paper is fed out in the tangential plane direction of the circular outer peripheral surface of the roller through the nip portion of the roller. That is, the portion of the recording paper fed in an oblique direction with respect to the platen surface is conveyed while being pressed against the platen surface. Further, the portion of the recording paper fed out from the nip portion first rides on the guide surface protruding from the platen surface and is guided while being supported by the guide surface. Therefore, the deflection of the recording paper can be suppressed between the nip portion and the platen surface. Further, since the guide surface is formed so as not to protrude from the tangential plane that defines the feeding direction of the recording paper, the guide surface does not obstruct the conveyance of the recording paper.

Here, the inclination of the inclined surface portion of the guide surface is preferably the a tilt angle along the tangent plane. In this way, the feeding direction of the recording sheet fed from the nip portion and the direction of the inclined surface portion of the guide surface coincide with each other, so that the bending of the recording sheet can be reliably prevented.

It is also desirable to Ru with a rake face which is inclined to the side opposite to the side of the print head taken to continuously to the inclined surface portion toward the side of the nip portion. For example, when the portion of the recording paper fed out from the nip is bent or folded, such a portion is scooped up by the scooping surface portion toward the inclined surface portion on the downstream side. Paper can be transported smoothly.

Furthermore, in succession to the rake face, it is desirable that the protruding surface protruding toward the front Symbol nip Ru is formed. By forming the protruding surface portion, the gap between the suction platen and the roller can be narrowed, so that it is possible to prevent the occurrence of a paper jam state where the recording paper is jammed in this portion.

Here, the vacuum platen can be formed of the structure defined by the upper end surface of the Li Bed extending in the conveying direction of the recording paper. In this case, it is possible to define a guide surface by the upper end surface of the ribs, also the projecting rib portion to form a protruding rib portion you projecting to the side of the nip portion than the end surface of the vacuum platen What is necessary is just to prescribe | regulate the said protrusion surface part by the upper end surface of.

The platen surface has an upward horizontal surface portion, and the pair of rollers are horizontally disposed so as to be pressed against each other in the vertical direction.

  On the other hand, the printer of the present invention is characterized by having the recording paper transport path structure having the above-described configuration. In particular, it is desirable that an ink jet printer in which the print head is an ink jet head and the suction platen is opposed to an ink nozzle surface of the ink jet head has the recording paper transport path structure configured as described above.

  In the recording paper conveyance path structure of the present invention, the guide surface formed on the end portion of the platen surface on the side of the nip portion of the roller is guided while being supported by the portion of the recording paper fed in the direction of pressing from the nip portion to the platen surface. The Therefore, it is possible to suppress the deflection of the recording paper that occurs in the portion between the nip portion and the platen surface, and it is possible to prevent adverse effects such as a decrease in paper feed accuracy and a paper jam caused by the deflection of the recording paper.

  Further, in an ink jet printer having the recording paper transport path structure, the recording paper delivered to the platen surface from the nip portion of the pair of rollers does not cause a decrease in paper feeding accuracy, a paper jam, and the like, so that the print quality is deteriorated. Therefore, the printing operation can be performed efficiently.

1 is an external perspective view of a roll paper printer to which the present invention is applied. FIG. 2 is an external perspective view of a roll paper printer with an open / close lid fully opened. It is a schematic longitudinal cross-sectional view of a roll paper printer. It is the perspective view and side view which show a recording paper conveyance path structure. It is explanatory drawing which shows the principal part of a recording paper conveyance path structure. It is explanatory drawing which shows the effect of a recording paper conveyance path structure. It is explanatory drawing which shows the subject of this invention.

  Hereinafter, an embodiment of a printer having a recording paper conveyance path structure to which the present invention is applied will be described with reference to the drawings.

(overall structure)
FIG. 1 is an external perspective view of an ink jet type roll paper printer according to the present embodiment, and FIG. 2 is an external perspective view of a state in which the opening / closing lid is fully opened. The roll paper printer 1 has a printer body 2 having a substantially rectangular parallelepiped shape as a whole, and an opening / closing lid 3 attached to the front surface of the printer body 2. A recording paper discharge port 4 having a predetermined width is formed on the front surface of the outer case 2 a of the printer body 2. A paper discharge guide 5 protrudes forward below the recording paper discharge port 4, and a lid opening / closing lever 6 is disposed on the side of the paper discharge guide 5. Below the paper discharge guide 5 and the lid opening / closing lever 6 in the outer case 2a, a rectangular opening 7a for taking in and out the roll paper of the roll paper storage portion 7 formed in the printer main body 2 is formed. The opening 7 a is sealed by the opening / closing lid 3.

  When the lid opening / closing lever 6 is operated, the lock (not shown) of the opening / closing lid 3 is released. When the paper discharge guide 5 mounted on the opening / closing lid 3 is pulled forward after unlocking, as shown in FIG. 2, the opening / closing lid 3 opens until it becomes almost horizontal with the lower end as the center. When the opening / closing lid 3 is opened, the roll paper storage unit 7 is opened, and the suction platen 8 defining the printing position is moved together with the opening / closing lid 3, so that the roll paper storage unit 7 moves to the recording paper discharge port 4. The incoming recording paper transport path is opened, and the roll paper 9 can be easily replaced from the front of the printer.

  On the platen surface 8 a of the suction platen 8, a suction portion 11 for sucking the long recording paper 10 fed out from the roll paper 9 is formed. The suction unit 11 includes a plurality of groove-shaped suction sections partitioned by a plurality of vertical ribs 12 and suction holes 13 formed in the bottom surface of each suction section.

(Internal structure)
FIG. 3 is a schematic vertical cross-sectional view showing the internal configuration of the roll paper printer 1 when the roll paper storage unit 7 is viewed from the right side of the printer. Inside the roll paper printer 1, a roll paper storage unit 7 is formed at the center in the width direction of the printer main body frame 14. A roll paper 9 is stored in the roll paper storage unit 7 so as to be able to roll in a horizontally placed state facing the printer width direction.

  A head unit frame 15 is horizontally attached to the upper end of the printer main body frame 14 above the roll paper storage unit 7. The head unit frame 15 includes a carriage 17 on which the inkjet head 16 is mounted, and a carriage guide shaft 18 that guides the movement of the carriage 17 in the printer width direction. The inkjet head 16 is mounted on the carriage 17 so that the ink nozzle surface 16a faces downward. The carriage guide shaft 18 extends horizontally in the printer width direction, and the head unit frame 15 includes a carriage motor 19 and a timing belt 20 for reciprocating the carriage 17 along the carriage guide shaft 18. A transport mechanism is arranged.

  A platen frame 21 that extends horizontally in the front-rear direction of the printer is disposed below the inkjet head 16. A suction platen 8 is attached to the platen frame 21 horizontally in the printer width direction. The suction platen 8 faces the inkjet head 16 with a certain gap, and defines the printing position of the inkjet head 16. A centrifugal fan 30 is attached to the back side of the back plate portion 14 a of the printer main body frame 14 at the rear of the roll paper storage unit 7 for performing suction by the suction unit 11 of the suction platen 8.

  On the rear side of the suction platen 8, a paper feed roller 22 is stretched horizontally in the printer width direction. A paper press roller 23 having a predetermined width is pressed against the paper feed roller 22 with a predetermined pressing force. The paper feed roller 22 is rotationally driven by a paper feed motor (not shown) mounted on the printer main body frame 14.

  A tension guide 24 that is bent downward is attached to the rear end of the platen frame 21. The recording paper 10 fed out from the roll paper 9 loaded in the roll paper storage unit 7 is drawn obliquely upward and then bent by the tension guide 24, and then extends in the horizontal direction to reach the recording paper discharge port 4. It is conveyed along the recording paper conveyance path.

  Below the tension guide 24, a feeding roller 25 is disposed horizontally in the printer width direction. The feeding roller 25 is for feeding the recording paper 10 from the roll paper storage unit 7, and is arranged on the upstream side of the tension guide 24 in the recording paper conveyance path. The feeding roller 25 is rotationally driven by a feeding motor (not shown). A second presser roller 26 having a predetermined width is pressed against the feeding roller 25 so that the second presser roller 26 is attached to the lower side of the suction platen 8 so as to extend rearward. The lever 27 is attached to the tip portion. When the presser lever 27 is biased downward by the spring force, the second presser roller 26 is pressed against the feeding roller 25.

  Here, the suction platen 8, the tension guide 24, the paper feed roller 22, the presser lever 27, and the second presser roller 26 are mounted on the side of the opening / closing lid 3, and move together with the opening / closing lid 3a.

  The portion of the recording paper 10 fed out from the roll paper 9 is conveyed while being sucked by the platen surface 8a of the suction platen 8 and passes through the printing position. At the printing position, the carriage 17 is reciprocated along the carriage guide shaft 18 and printing is performed by the inkjet head 16 mounted thereon. After a series of line printing in the width direction of the recording paper 10 is completed, the paper feeding roller 22 and the feeding roller 25 are rotationally driven to feed the recording paper 10 by a predetermined pitch. After this, the next line is printed. Thus, the recording paper 10 is printed by the inkjet head 16 while being intermittently sent out at a predetermined pitch.

  In the roll paper printer 1 of this example, a fanfold paper insertion portion 31 is formed on the rear side of the head unit frame 15. A guide plate mounting portion 32 is disposed in the insertion portion 31, and a fanfold paper guide (not shown) can be detachably mounted from the rear side. When the paper guide is mounted, the conveyance path for guiding the recording paper 10 between the paper feed roller 22 and the paper presser roller 23 from the roll paper storage unit 7 side through the tension guide 24 is blocked and inserted from the rear side of the printer. In addition, a fanfold paper conveyance path is formed, and printing can be performed on the fanfold paper fed from the rear side of the printer through this path.

(Recording paper transport path structure)
Next, with reference to FIGS. 4 to 6, a recording paper conveyance path structure for sending the recording paper from the nip portion of the paper feeding roller 22 and the paper pressing roller 23 to the platen surface 8 a of the suction platen 8 will be described. 4A is a perspective view showing a recording paper transport path structure, and FIG. 4B is a side view thereof. FIG. 5 is an explanatory diagram showing, in an enlarged manner, a portion E surrounded by a one-dot chain line in FIG. FIG. 6 is an explanatory diagram showing the recording paper transport operation by the recording paper transport path structure.

  4 and 5, the platen surface 8 a of the suction platen 8 is formed on the plurality of vertical ribs 12 having a constant thickness arranged at a predetermined pitch along the recording paper conveyance direction. It is defined by the end face. The platen surface 8a is a horizontal surface extending in the printer width direction except for the upstream end portion 8b in the recording paper conveyance direction. A paper feed roller 22 is disposed at a position adjacent to the upstream side of the upstream end portion 8b of the platen surface 8a, and a paper press roller 23 is pressed against the paper feed roller 22 from above.

  As shown in FIG. 5, the nip portion 52 between the paper feed roller 22 and the paper presser roller 23 is at a position offset by a step A upward with respect to the horizontal plane P1 where the platen surface 8a is located. Further, the paper pressing roller 23 is arranged at a position slightly offset in front of the printer with respect to the paper feeding roller 22, and the line segment L1 connecting the centers 22a and 23a is slightly inclined upward toward the front side of the printer. Yes. Therefore, the feeding direction of the recording paper 10 fed out from the nip portion 52, that is, the tangential plane P2 of the circular outer peripheral surfaces of both rollers 22 and 23 passing through the nip portion 52, the platen surface 8a from the nip portion 52 toward the platen surface 8a. The inclined surface is inclined by an angle θ1 in a direction approaching the surface 8a.

  Here, the upper end surface of each vertical rib 12 on the platen surface 8a is a horizontal surface portion 12a except for the upstream end portion 8b. In the upstream end portion 8b, each vertical rib 12 is moved toward the upstream side. Thus, an inclined surface portion 12b that is continuous with the horizontal surface portion 12a is formed by this portion (as it approaches the nip portion 52). The inclined surface portion 12b is an inclined surface having an inclination angle substantially the same as the inclination angle θ1 of the tangential plane P2 that is the feeding direction of the recording paper from the nip portion 52, and does not protrude upward beyond the tangential plane P2. It is set to height.

  Each vertical rib 12 is formed with a portion that descends from above, and this portion forms a rake face portion 12c that slopes downward continuously from the inclined face portion 12b. Further, each vertical rib 12 includes a protruding rib portion 12e protruding forward from the vertical end surface 8d on the upstream side of the suction platen 8, and the leading end surface of the protruding rib portion 12e is continuous with the rake face portion 12c. The protruding surface portion 12d is curved and connected to the vertical end surface 8d.

  Next, with reference to FIG. 6, the recording paper conveyance operation by the recording paper conveyance path structure will be described. The recording paper 10 fed out from the nip portion 52 of the paper feeding roller 22 and the paper pressing roller 23 is fed out along the tangential plane P2 toward the platen surface 8a. The portion of the recording paper 10 fed from the nip portion 52 is first guided on the upper end surface portion of the vertical rib 12 that defines the upstream end portion 8b of the platen surface 8a. An inclined surface portion 12b that is inclined in a direction along the tangential plane P2 is formed on the upper end surface portion, and the recording paper 10 is supported by the inclined surface portion 12b toward the horizontal surface portion 12a. Guided.

  The recording paper 10 is supported from below by the inclined surface portion 12b in a state along the feeding direction from the nip portion 52. Therefore, the recording paper 10 is prevented from being bent downward in the gap 53 between the nip portion 52 and the platen surface 8a.

  Further, a rake face portion 12c is formed upstream of the inclined face portion 12b. When the portion 10a of the recording paper 10 between the nip portion 52 and the platen surface 8a is bent downward, it is supported by the scooping surface portion 12c and scooped up toward the inclined surface portion 12b. In particular, when a portion such as a fold (perforation) of the fanfold paper passes, the fold portion is likely to be bent downward as shown by a dotted line in the figure. Since such a portion is supported by the rake face portion 12c, the recording paper 10 is guided downstream without being greatly bent downward.

  Furthermore, a protruding surface portion 12d that protrudes toward the nip portion 52 side is formed continuously with the rake surface portion 12c. The protruding surface portion 12d narrows the gap 53 between the vertical end surface 8d on the upstream side of the platen surface 8a and the paper feed roller 22. Therefore, it can be avoided that the recording paper 10 is caught in the gap 53 and the paper jam occurs.

  Therefore, the portion of the recording paper 10 fed out from the nip portion 52 bends downward in the gap 53, and the feeding accuracy of the portion of the recording paper 10 conveyed on the platen surface 8a on the downstream side of this is lowered, so that the print quality is improved. There will be no adverse effect of lowering. Further, it is possible to prevent the recording paper 10 from falling into the gap 53 and falling into a paper jam state.

1 roll paper printer, 2 printer body, 2a exterior case, 3 open / close lid, 4 recording paper discharge port, 5 paper discharge guide, 6 lid open / close lever, 7 roll paper storage, 7a opening, 8 suction platen, 8a platen surface, 8b Upstream end portion, 8d vertical end surface, 9 roll paper, 10 recording paper, 11 suction portion, 12 vertical rib, 12a horizontal surface portion, 12b inclined surface portion, 12c rake face portion, 12d protruding surface portion, 12e protruding rib portion, 13 Suction hole, 14 Printer body frame, 15 Head unit frame, 16 Inkjet head, 16a Ink nozzle surface, 17 Carriage, 18 Carriage guide shaft, 19 Carriage motor, 20 Timing belt, 21 Platen frame, 22 Paper feed roller, 23 Paper presser Roller, 22a, 23a Center, 24 Tension guide, 25 Feeding roller, 26 Second presser roller, 27 Presser lever, 30 Centrifugal fan, 52 Nip part, 53 Clearance, P1 horizontal plane, P2 tangential plane, θ1 Tilt angle

Claims (7)

A recording paper transport path structure for sending the recording paper to the platen surface of the suction platen facing the print head via the nip portion of the pair of rollers;
The nip portion is at a position offset toward the print head with respect to the platen surface,
The pair of rollers is arranged so that a tangential plane passing through the nip portion becomes an inclined surface that is inclined in a direction approaching the platen surface as it goes from the nip portion to the platen surface,
The platen surface has an inclined surface portion that is inclined toward the print head toward the nip portion side of the platen surface, and guides the recording paper fed from the nip portion. A guide surface is formed,
The guide surface is a guide surface having a height that does not protrude from the tangential plane ,
The recording paper conveyance path structure according to claim 1, wherein the inclination of the inclined surface portion of the guide surface is an inclination angle along the tangential plane . 2. The recording paper transport according to claim 1 , wherein the guide surface includes a rake surface portion that is inclined to a side opposite to the print head side toward the nip portion side continuously to the inclined surface portion. Road structure. The recording paper transport path structure according to claim 2 , wherein a protruding surface portion protruding toward the nip portion is formed continuously with the rake surface portion. The platen surface is defined by an upper end surface of a rib extending in the recording paper conveyance direction,
The rib includes a protruding rib portion that protrudes toward the nip portion from the end of the suction platen,
The recording paper transport path structure according to claim 3 , wherein an upper end surface of the protruding rib portion is the protruding surface portion. The platen surface has an upward horizontal surface,
It said pair of rollers, the recording sheet conveying path structure according to any one of claims 1 to 4 is pressed against the vertical direction to each other are arranged horizontally. A printer having a recording paper conveyance path structure according to any one of claims 1 to 5 . The printer according to claim 6 , wherein the print head is an inkjet head, and the suction platen faces an ink nozzle surface of the inkjet head.

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